Abstract: Objective To investigate the p53 gene mutations in Chinese patients with epithelial skin cancers. Methods Biopsies of 22 squamous cell carcinoma(SCC)and 18 basal cell carcinoma(BCC)were analyzed by polymerase chain reaction denaturing gradient gel electrophoresis(PCR-DGGE) and DNA sequencing for alterations in the exons 5～8 of p53 tumor suppressor gene. Results p53 gene mutations were found in 32.5%(13/40)of tumor tissues and 92.3%(12/13) of the mutations occurred at sun exposed areas. 36.4%(8/22)of SCC tissues and 27.8%(5/18) of BCC tissues presented p53 gene mutations. Of the 13 mutations within the exons examined, 76.9%(10/13) were missense mutations and 23.1%(3/13) were nonsense mutations. Twelve of the 13 mutations were of single nucleotide substitutions. Six of the 13 mutations involved dipyrimidine sites, where a C was replaced by a T or CC was replaced by TT(five C→T transitions and one CC→TT transition). Conclusion Ultraviolet(UV) radiation might be related to the pathogenesis of skin cancer. Mutations of p53 gene caused by solar UV might play a significant role in UV tumorigenesis, although other carcinogens might also be involved.

Key words: Carcinoma,squamous cell, Carcinoma,basal cell, Genes,p53, Light